It as an Empty Subject
Level A2 · Sentence Basics
English sentences almost always need a subject, even when there's no real thing doing the action — it fills that grammatical slot without referring to anything specific. It's raining, It's 5 o'clock, and It's important to arrive early all use it as an empty subject: nothing is actually 'raining' or 'being 5 o'clock' — it is there purely because English requires a subject.
Common uses of empty it:
- Weather: It's raining, It's sunny, It's windy today — it never refers to a specific weather 'thing', just fills the subject position.
- Time, date, and distance: It's half past three; It's the 3rd of May; It's ten miles to the coast.
- General statements of opinion or necessity, often followed by an adjective + to-infinitive or that-clause: It's important to study; It's a shame that she couldn't come; It's obvious (that) he was right.
- it can also point back to something already mentioned (a normal pronoun use) — don't confuse this with empty it: I bought a book. It was expensive (it = the book, a real reference) vs It's expensive to travel abroad (it = empty, no specific reference).
The most common mistake is dropping it entirely, copying a language where the subject can be omitted — Is raining or Is important to study are both wrong in English; the empty subject it is required: It's raining, It's important to study. A second mistake is using there instead of it for weather, time, or opinion statements — There is raining or There is important to study are wrong; there introduces the existence of something new, while it fills an empty subject slot with no specific referent.
Look for it at the start of a sentence about weather, time, date, distance, or a general opinion/necessity, with nothing specific that it could be pointing back to — that's the empty subject use. If it clearly replaces a noun mentioned just before, it's a normal pronoun instead.